Laryngeal Muscle Tension Disorders: Voice Manifestations
"Laryngeal muscle tension disorder" is the general term given to describe a variety of conditions that can cause both voice and breathing problems. When the voice is primarily affected, these disorders are also called muscle tension dysphonia. This page provides more information on how laryngeal muscle tension dysphonia can affect the voice.
VOICE DISORDERS AND LARYNGEAL MUSCLE TENSION DYSPHONIA:
When the disorder primarily affects the voice, the condition is called a muscle tension dysphonia. ("Dysphonia" is the term used to describe an abnormal sounding voice). Speaking and singing requires extremely high coordination of many muscles, and under some circumstances these muscles may lose some of this coordination or they may contract inappropriately. This can produce a hoarse voice, neck pain, neck fatigue, and even complete loss of the voice.
In most cases the problem in muscle tension dysphonia (MTD for short) can be said to exist at the level of the neck or the larynx. It differs from a different disorder called spasmodic dysphonia (SD); in SD the problem is felt to originate within a part of the brain called the basal ganglia and it is treated quite differently.
Movements of the vocal folds during speech are described in more detail in the page on anatomy of the larynx. Briefly, when we speak voiced sounds (the vowels), the vocal folds are brought together ("adducted") and they vibrate as bursts of air pass through them. The vocal folds need to be adducted with the proper amount of force so that they can open without significant effort. Muscle tension dysphonias develop when either muscles in the larynx or the muscles in the neck contract improperly during speech.
One of the most common types of muscle tension dysphonias (MTD) occur when there is a compression of the vocal folds during speech. To understand this, imagine that your index and middle fingers represent the vocal folds. Your fingernails would then be in the same spot as the arytenoids (each arytenoid is a small piece of cartilage attached to the back of the vocal fold and also attached to the muscles that move the folds.) The vocal folds should close just as if your were bringing your fingers together (like a scissors) .
In this first type of MTD, instead of closing like a scissors the vocal folds also contract as they close. Using the analogy above, it is as if the fingers bent as they closed instead of remaining straight. During the exam, in an individual with MTD the arytenoids inappropriately come forward towards the anterior part of the larynx during speech. This anterior/posterior compression requires extra muscle effort and can therefore produce both fatigue and pain with voice use.
A second type of MTD occurs when the false vocal folds come together during speech. Normally, the false vocal folds should remained separated as the true vocal folds are adducted. Some individuals develop a speaking pattern in which they "bear down" and the false folds inappropriately contact each other during speech. This is called "false vocal fold phonation" or "plicae ventricularis".
False vocal fold phonation can arise on its own, but it can also occur in compensation for weak closure of the true vocal folds. If the true folds do not come together with enough force during attempted speech, air will leak out. As a result, some individuals will involuntarily bring their false vocal folds together to try to generate some sort of sound. In some cases, you can actually see vibration of the false vocal folds on a strobe exam. However, the voice quality is almost always quite poor.
More severe cases of MTD can produce complete loss of voice. Occasionally, the vocal folds are brought together with such force that air cannot escape between them. This disorder resembles spasmodic dysphonia, though there are clues in the history and the exam that can help distinguish the two. In other cases, the vocal folds themselves are tensely contracted but a small gap is left when the patient tries to talk. This can produce a voice that is essentially nothing more than a strong whisper.
A variety of factors can lead to laryngeal MTD. One common situation occurs after a severe case of laryngitis. Acute laryngitis results in swollen inflamed vocal folds, and as a result it is very painful to talk. Patients will therefore whisper during the active infection. In some cases, the patient will continue to talk in this fashion even after the active infection has gone away.
Stress plays a key role in MTD, and therefore one may here the usual statement that these disorders are "all in your head". However, the fundamental problem is improper contraction of the folds and the treatment must directed towards restoring normal vocal fold movement. If there are psychological stressors, these should also be addressed.
Diagnosis of MTD can be difficult since the vocal folds actually have a relatively normal appearance at rest. It is only during speech tasks that one sees the abnormal contraction of the muscles.
The key treatment for MTD is speech and voice therapy. Significant reduction in throat discomfort and improvements in voice quality can occur with proper treatment. Unfortunately, many insurance companies do not recognize this as a health problems and getting approval for needed medical care can be difficult.
The photo below on the left shows the larynx during speech in a woman with laryngeal MTD. You cannot actually see the true vocal folds in this picture since the false vocal folds are inappropriately closing and they block the view of the true vocal folds lower down. Her voice in this situation was both hoarse and strained.
The photo on the right is taken while the same patient is being coached by a speech pathologist. Note that the appearance of the vocal folds is dramatically different. Instead of being pinched together, the false vocal folds are appropriately separated. The true vocal folds can actually be seen and they are much less tense. Stroboscopic exam shows very little movement in the first case, but nice vibration when the patient is being coached by the speech pathologist.